package main

import (
	"bytes"
	"fmt"
)

func main() {
	var contents string
	b1 := bytes.NewBufferString(contents)
	fmt.Printf("Lan: %d, Cap: %d.\n", b1.Len(), b1.Cap())

	contents = "一二三四五"
	b1.WriteString(contents)
	fmt.Printf("Lan: %d, Cap: %d.\n", b1.Len(), b1.Cap())
	
	contents = "67"
	b1.WriteString(contents)
	fmt.Printf("Lan: %d, Cap: %d.\n", b1.Len(), b1.Cap())
}
